When you first start to crochet your tendency is to be kind of cramped and tight , because you trying WAY to hard to do the job.
How can you over come that:
Think of crochet as a HOBBY, not a job.
Think of crochet as inconsequential. It will not matter 100 years from now, if you stitch was even or not. Just do it and relax, since nobody will get hurt.
Think of the finished product not in the terms of HOW it will look, but THAT you MADE it, that you are growing personality by being CAPABLE, that you are getting better.
Think of the person you make it for and why you are making it.
Those things help you to relax and get to your goal: FINISH the started task.
Are you chains still too tight? Use a bigger hook.
Do you have problems pushing through your tight chains? Use a smaller hook that is very pointy.
Even most avid crochet expert’s slip stitches and chains will be tighter than their other stitches, if they do not watch it, because in those stitches is the least amount of yarn and hence they are tighter by sheer physics. Chains and slip stitches therefore have the tendency to be smaller than the rest of the crochet fabric.
You just keep practicing and the tension will become second nature to you. You didn’t quit driving a car, because you ” hopped” on the road, because your foot gave too much gas in an irregular interval. Same thing with crochet and everything else in life: You crawl before you walk and before you know it: You are running!